Three-wire system of electrical distribution.



P. H. THOMAS.

THREE-WIRE SYSTEM OF ELECTRICAL DISTRIBUTION.

, APPLICATION FILED OCT. 9, 1909.

Patented Sept. 15,1914.

"V/Q; ATTORNEY IIVI/EIIVTOR WITNESSES. W

UNI ED STATES PATENT oFFIc PERCY H. THOMAS, OE MONTCLAIR, NEW JERSEY, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO COOPER HEWITT ELECTRIC COMPANY, OF HOBOKEN, NEW JERSEY, A

conromrrou or NEW JERSEY.

THBEE WIRE SYSTEM OF ELECTRICAL DISTRIBUTION.

Specification of Letters Batent. Patented Sept. 15, 1914:.

Original applipationfiled January 21, 1903, Serial No. 139,957. Divided and this application filed October 9, 1909. Serial No. 521,949. 7

of Electrical Distribution, of which the fol lowing is a specification.

The object of the present invention is to provide a system of circuits and apparatus whereby a three-wire direct current consumption circuit can be supplied from an alternating source. Y

In carrying out my invention, I control the distribution of the currents derived from the source to the three-Wire circuit by means of'rectifiers; and I have found that suitable devices for this purpose are the gas or vapor electric apparatus invented by Peter Cooper Hewitt, the general teatures'of such apparatus having been described in certain patents issued to him on the 17th day otSeptember, 1901. Attention is directed to patents Nos. 682,690to 682,699 inclusive. The apparatus referred to consists, in general, of a suitable container within which is a gas or vapor and two or more electrodes. The negative electrode may conveniently be of mercury, and the positive electrode or electrodes may be of iron. It is'known that when apparatus of this description is subjected to the proper conditions, current will traverse the gas or vapor within the container in a given direction, afterthe original resistance to starting has once been broken down, while it will oppose to the flow of current in they opposite direction, a practically prohibitive resistance. 7

In my United States Patent No. 930,325 of August 3rd, 1909, I have shown and described means for supplying direct current from an alternating source to a plurality of work or consumption circuits admitting of such correlation as to serve, if desired, the purposes of three-wire distribution. In the presentinvention, the distribution of ourrentfrom the alternating source is such as to 'feed a, typical three-wire system in which translating devices are arranged on opposite sides of a neutral wire running back to the source and connected to the usual. mains.

The drawings, Figures 1, 2, 3 and 4, are diagrams illustrating the connections of a three-wire consumption circuit with various types of alternating current sources.

In the drawings, 1, 2 and 3, represent the wires of a three-wire consumption circuit, 2 being the neutral wire, and 1 and 3 the mains.

Referring more particularly to'Fig. 1, 10 represents a source of single-phase alternating current, which may be either a singlephase generator or a transformer delivering single-phase currents. The wire 2 is connected to the source at the middle point between the two parts, 11 and 12, of the winding of. the source. The other terminals of these parts or windings are connected to the mains of the three-wire circuit through rectifiers, 5 and 6, as shown. It will be seen that one of the terminals of the winding 11 is connected to the main conductor, 3, through a current rectifier 5, and also to the main conductor 1, through a current rectifier 6. The two rectifiers named are shown in reverse positions and the direction of current flow is indicated by arrows. 'For convenience, the rectifier 5 may be termed a positive device, and. the rectifier 6 a negative device. The outer terminal of the winding 12 also is connected to the main conductor 3,

Stated generally, one of the main conductors is connected to each outer terminal of the source through a positive device, and the other main conductor is connected to each cuter terminal through a negative device.

Bearing in mind that the current rectifiers permit a flow of current only in the directions' indicated bythe arrows, it is clear that a positive impulse from the outer terminal ofthe winding 11 will enter the consumption circuit through the current rectifier 5, and will pass by way of the wire 9 to the main conductor 3, and thence across one side, 40, of the circuit to the wire 2, running to the neutral point of the source. A positive impulse from the outerterminal of the winding 12, will pass to the main conductor, through the positive device 5, and will traverse a similar course back to the neutral point.

Negative impulses from the terminals of the source pass to the main conductor 1, traversin through t e other side, 41, of the three-wire wire circuit supplied by the source 10, is

circuit, and also passing through,in one instance, the wire, 2, the rectifier 6, and the wire 7, and in the other instance the wire 14-, rectifier 6, and wire 13. 1

It will be understood that when the two sides of the three-wire circuit are evenly balanced, there will be'no resultant current in the neutral wire, and the positive impulses will pass across the entire system, through both sides thereof (40 and 41), and will return either through thewires 8 and 7 and the rectifier 6 between those wires, or throu h the wires 14 and 13, and the include rectifier 6. Negative impulses will similarly pass through the entire three-wire circuit under the conditions named.

In Fig. 2, 10 may be any source-of two phase or four-phase alternating current having a neutral point, as indicated at 4. A study of the diagram shows that, as before, one of the main conductors of the threeconnected to. each outer terminal of the source through a positive device, while the other main conductor is connected to each outer terminal through a negative device. This applies also to the systems illustrated in Figs. 3-and 4 The positive impulses from the source are delivered to one side of the three-wire circuit, and the ne ative im- .pulses to the other side, and t 'e neutral wire acts, as before, to. carry current onl when the balance of the system is disturbe The source illustrated in Fig; 3, at 10, may

-be either a three-phasegenerator or a transformer. delivering three-phase currents or any other source of three-phase alternating currents. The diagram constituting this figure does not differ, essentially, from these.

already described, except in the character of the source and the necexary modifications due to such different character. The same is true respecting the diagralm Fig. 4;.- In a ternating curthis instance, the source 0 rents is diagrammatically illustrated as a group of transformers delivering six-phase currents and receiving its energy from a three-phasesource. The wires 18, 19 and 20, are the leads from a source of threephase currents and the are connected as shown with three trans ormers, 21, 22 and 23. Cooperating with these transformers, respectively, are the secondaries 24, 25 and 26, which, by virtue of well-known connecthe neutral wire 2, and passing.

tions illustrated by wires 27, 28,29, 30, 31, 32, 33 and 34, are capable of delivering sixphase currents. The neutral wire 2, in this instance, is connected to the middle points of the secondaries 2 1, 25 and 26. The connections from the delivery wires of the six-phase system are similar to those already described and shown in connection with the earlier figures of the drawing.

The illustrated distribution systems arev shown in this application merely as typical of'systems of distribution of the general character described. It will be'understood that the invention is applicable to systems in which the alternating source has any desired number of phases. The system I have described has a distinct advantage over 5- tems not utilizing separate containers or the anodes connected to points of different.

potential in the supply, in that the tendency to arc or the failure of the cathode reluctance of the anodes isgreatly reduced by the use'of the separate containers. The nature of this action is not definitely roved,

though it may be due to-the fact t at the power current flowing from one terminal of the supply through one anode'does not pass in the same receptacle that contains another anode for the moment negative potential.

This application is adivision of m ap lication filed May 6th, 1903, Serial um r 155,922 which in turn is a division of my application filed January 21st, 1903, Serial Number 139,957.

I claim as my invention: 1. In a system of electrical distribution,

impressed with a the combination with a source of single phase alternating current having an intermediate poin't, a direct current work circuit and two vapor rectifiers, each including an exhausted container and two main electrodes,

one a main anode and the other a re-constructmg vaporizable cathode, of connections from the terminals of the source tov said :main anodes and from the cathodes to "the work circuit, and a connection from the work circuit to the said intermediate point, whereby the current impulses occurring the combination with an alternating supply,

1n one: container are rectified independently of a direct current work circuit-havinga posltive main and a negative main and means for passing positively directed im ulses from the several terminals of the sai sup ply to said positive main and for s u pressing oppositely directed current impu sald supply, said means depending upon the starting reluctance of electrodes in a vacuum space, separate containers inclosing said electrodes and a connection between said negative main and an intermediate point of said supply.

3. In a system of electrical distribution,

the combination with an alternating supply other times, said means depending upon the starting resistance of an electrode in a vacuum space, of separate containers for 15 said electrodes and a connection from said negative main to said neutral point.

Signed at New\York, in the county of New York, and State of New York this 8th day of October, A. D. 1909.

PERCY H. THOMAS.

Witnesses THOS. H. BROWN,

' WM. H. CAPEL. 

